Leprosy is a rare disease in Bulgaria. There have been 58 cases registered during the last one hundred years. The number of leprous patients in 1980 was 13, most of them came from the northern part of the country. The epidemiological studies indicate, that in some of the cases the infection has been acquired in other countries (South America, Romania, Jugoslavia, The Caucasian region), in most patients, however, the disease has been acquired in Bulgaria by an unknown source of infection. The most frequent clinical form is Lepra lepromatosa and the rarest Lepra indeterminata. All patients have been treated with 4,4-diaminodiphenyl sulphone (DDS), combined with Thiambutosine. The length of treatment depends upon the clinical type of leprosy. The results of the treatment are promising. Only two patient still reveal acid fast bacilli.